273 Performance build possibilities.

Demonracer said
Higher compression on the SBM is detrimental to head gaskets. Ask me how I know, I was running 12.0 to 1 compression pistons in a street car with a 273 in the early 70's. I ended up contacting Ed Hamburger and he spec'd out putting SS o-rings in my block and running his copper sandwich gaskets. This indeed stopped me from blowing out head gaskets.

I had a 340 block o-ringed with inconel wire and copper gaskets in the 80's . The new way is copper o-rings in the head and multi layer steel gaskets. They will withstand 60# of boost. He still does some blocks but now copper rings and steel gaskets. Aluminum blocks he leaves the sleeves protrude the block .002 -.003 due to block growth.